基于元胞自动机法的7055铝合金动态再结晶变形参数优化（英文）

发布时间：2019-04-09 07:36

【摘要】：为了研究7055铝合金在热压缩过程中的组织演变规律,基于元胞自动机法(CA)建立7055铝合金动态再结晶(DRX)模型。为了获得模型的材料参数,进行单道次热压缩实验,通过最小二乘法拟合获得7055铝合金的位错密度模型、形核率模型和再结晶晶粒长大模型。研究应变、应变速率、变形温度和初始晶粒尺寸对热压缩过程中显微组织演变的影响。结果表明:在热压缩过程中,动态再结晶使材料晶粒明显细化。大应变、高温和低应变速率有利于晶粒细化;动态再结晶晶粒的稳态晶粒尺寸与初始晶粒大小无关,而取决于温度和应变速率的变化;分析热压缩过程动态再结晶动力学规律。由CA仿真流变应力值和仿真组织图与实验结果的对比可知,所建立的基于CA法的动态再结晶模型能有效地预测7055铝合金在热变形过程中的动态再结晶组织演变规律。
[Abstract]:In order to study the microstructure evolution of 7055 aluminum alloy during hot compression, the dynamic recrystallization (DRX) model of 7055 aluminum alloy was established based on (CA). The dislocation density model, nucleation rate model and recrystallization grain growth model of 7055 aluminum alloy were obtained by least square fitting in order to obtain the material parameters of the model. The effects of strain, strain rate, deformation temperature and initial grain size on microstructure evolution during hot compression were studied. The results show that dynamic recrystallization makes the grain finer obviously in the process of hot compression. Large strain, high temperature and low strain rate are beneficial to grain refinement, the steady grain size of dynamic recrystallization grain is independent of initial grain size, but depends on the change of temperature and strain rate, and the dynamic recrystallization kinetics law of hot compression process is analyzed. The dynamic recrystallization model based on CA method can effectively predict the dynamic recrystallization microstructure evolution of 7055 aluminum alloy during hot deformation according to the comparison of CA simulation flow stress and simulation microstructure diagram with the experimental results. The results show that the dynamic recrystallization model based on CA method can effectively predict the dynamic recrystallization microstructure evolution of 7055 aluminum alloy during hot deformation.
【作者单位】：南京航空航天大学机电学院;中南大学机电工程学院;
【基金】：Projects(51175257,51405520) supported by the National Natural Science Foundation of China
【分类号】：TG146.21

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